1. Field of the Invention
The invention relates to a displacement unit for a manipulation system.
2. The Prior Art
From DE 41 06 689 Al a method for controlling a processing machine is known, in particular an assembly machine and similar processing machine. The latter comprises a plurality of workpiece carriers, which are moved past workstations on a moving track or work line in transport direction. The latter are designed respectively for at least one prespecified procedure and are controlled at least partly by an electronic control unit. Each workstation has its own electronic control unit, which is equivalent to the control units of other workstations, whereby the control unit of each workstation only cooperates with the immediately following and/or immediately preceding workstation via a data and control line. At the first workstation an electronic protocol is established for each workpiece carrier, which in addition to an identification identifying or characterizing said workpiece carrier contains the work to be performed in transport direction at subsequent workstations. Said protocol is then sent according to the work stages via a data line from the control unit of the preceding workstation to the control unit of the subsequent workstation. The disadvantage of this design is that the individual workstations comprise various different components according to the work to be performed, which excludes the serial manufacture of the various components. In this way it is not possible to produce such an assembly machine using standardized individual components, which is disadvantageous for the manufacturing costs of such an assembly machine. A further disadvantage is that once a production process has been commenced it is not possible to intervene to correct an erroneous protocol for example. Furthermore, the central monitoring or direct programming of a particular workstation is not possible for example with an additional simulation procedure.
EP 0 240 965 shows a compact electrohydraulic switching module which is used, for example, for driving displacement units which comprises a valve piston and a valve housing surrounding the valve piston with a drive arrangement formed by a coil, whereby the drive arrangement is driven by a command processing element, for example a microprocessor.
In EP 0 275 992, a method for driving a machine system, for example production lines, conveyor systems etc, with several actuators, especially electric motors but also other electrically controllable and electromechanical actuating devices are described, whereby some of the actuators are combined into a group and a control unit is assigned to each of the actuators in this group.
Similarly, a decentralized drive, for example of a displacement unit, is also described in FR 2 657 807.